[PATCH bpf-next 1/4] bpf: export bpf_sock for BPF_PROG_TYPE_CGROUP_SOCK_ADDR prog type

[PATCH bpf-next 1/4] bpf: export bpf_sock for BPF_PROG_TYPE_CGROUP_SOCK_ADDR prog type

[Stanislav Fomichev]

And let it use bpf_sk_storage_{get,delete} helpers to access socket
storage. Kernel context (struct bpf_sock_addr_kern) already has sk
member, so I just expose it to the BPF hooks. Using PTR_TO_SOCKET
instead of PTR_TO_SOCK_COMMON should be safe because the hook is
called on bind/connect.

Cc: Martin Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 include/uapi/linux/bpf.h |  1 +
 net/core/filter.c        | 16 ++++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index ae0907d8c03a..8815fc418cde 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3247,6 +3247,7 @@ struct bpf_sock_addr {
 	__u32 msg_src_ip6[4];	/* Allows 1,2,4-byte read an 4-byte write.
 				 * Stored in network byte order.
 				 */
+	__bpf_md_ptr(struct bpf_sock *, sk);
 };
 
 /* User bpf_sock_ops struct to access socket values and specify request ops
diff --git a/net/core/filter.c b/net/core/filter.c
index a5e4ac7fcbe5..37c4a2fd559b 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5922,6 +5922,10 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 	case BPF_FUNC_skc_lookup_tcp:
 		return &bpf_sock_addr_skc_lookup_tcp_proto;
 #endif /* CONFIG_INET */
+	case BPF_FUNC_sk_storage_get:
+		return &bpf_sk_storage_get_proto;
+	case BPF_FUNC_sk_storage_delete:
+		return &bpf_sk_storage_delete_proto;
 	default:
 		return bpf_base_func_proto(func_id);
 	}
@@ -6828,6 +6832,13 @@ static bool sock_addr_is_valid_access(int off, int size,
 		if (size != size_default)
 			return false;
 		break;
+	case offsetof(struct bpf_sock_addr, sk):
+		if (type != BPF_READ)
+			return false;
+		if (size != sizeof(__u64))
+			return false;
+		info->reg_type = PTR_TO_SOCKET;
+		break;
 	default:
 		if (type == BPF_READ) {
 			if (size != size_default)
@@ -7778,6 +7789,11 @@ static u32 sock_addr_convert_ctx_access(enum bpf_access_type type,
 			struct bpf_sock_addr_kern, struct in6_addr, t_ctx,
 			s6_addr32[0], BPF_SIZE(si->code), off, tmp_reg);
 		break;
+	case offsetof(struct bpf_sock_addr, sk):
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sock_addr_kern, sk),
+				      si->dst_reg, si->src_reg,
+				      offsetof(struct bpf_sock_addr_kern, sk));
+		break;
 	}
 
 	return insn - insn_buf;
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog

[PATCH bpf-next 2/4] bpf: export bpf_sock for BPF_PROG_TYPE_SOCK_OPS prog type

[Stanislav Fomichev]

And let it use bpf_sk_storage_{get,delete} helpers to access socket
storage. Kernel context (struct bpf_sock_ops_kern) already has sk
member, so I just expose it to the BPF hooks. I use
PTR_TO_SOCKET_OR_NULL and return NULL in !is_fullsock case.

I also export bpf_tcp_sock to make it possible to access tcp socket stats.

Cc: Martin Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 include/uapi/linux/bpf.h |  1 +
 net/core/filter.c        | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 8815fc418cde..d0a23476f887 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3299,6 +3299,7 @@ struct bpf_sock_ops {
 	__u32 sk_txhash;
 	__u64 bytes_received;
 	__u64 bytes_acked;
+	__bpf_md_ptr(struct bpf_sock *, sk);
 };
 
 /* Definitions for bpf_sock_ops_cb_flags */
diff --git a/net/core/filter.c b/net/core/filter.c
index 37c4a2fd559b..8c18f2781afa 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -6147,6 +6147,14 @@ sock_ops_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_get_local_storage_proto;
 	case BPF_FUNC_perf_event_output:
 		return &bpf_sockopt_event_output_proto;
+	case BPF_FUNC_sk_storage_get:
+		return &bpf_sk_storage_get_proto;
+	case BPF_FUNC_sk_storage_delete:
+		return &bpf_sk_storage_delete_proto;
+#ifdef CONFIG_INET
+	case BPF_FUNC_tcp_sock:
+		return &bpf_tcp_sock_proto;
+#endif /* CONFIG_INET */
 	default:
 		return bpf_base_func_proto(func_id);
 	}
@@ -6882,6 +6890,11 @@ static bool sock_ops_is_valid_access(int off, int size,
 			if (size != sizeof(__u64))
 				return false;
 			break;
+		case offsetof(struct bpf_sock_ops, sk):
+			if (size != sizeof(__u64))
+				return false;
+			info->reg_type = PTR_TO_SOCKET_OR_NULL;
+			break;
 		default:
 			if (size != size_default)
 				return false;
@@ -8053,6 +8066,19 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type,
 		SOCK_OPS_GET_OR_SET_FIELD(sk_txhash, sk_txhash,
 					  struct sock, type);
 		break;
+	case offsetof(struct bpf_sock_ops, sk):
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(
+						struct bpf_sock_ops_kern,
+						is_fullsock),
+				      si->dst_reg, si->src_reg,
+				      offsetof(struct bpf_sock_ops_kern,
+					       is_fullsock));
+		*insn++ = BPF_JMP_IMM(BPF_JEQ, si->dst_reg, 0, 1);
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(
+						struct bpf_sock_ops_kern, sk),
+				      si->dst_reg, si->src_reg,
+				      offsetof(struct bpf_sock_ops_kern, sk));
+		break;
 	}
 	return insn - insn_buf;
 }
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog

[PATCH bpf-next 3/4] bpf/tools: sync bpf.h

[Stanislav Fomichev]

Add sk to struct bpf_sock_addr and struct bpf_sock_ops.

Cc: Martin Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 tools/include/uapi/linux/bpf.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index ae0907d8c03a..d0a23476f887 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3247,6 +3247,7 @@ struct bpf_sock_addr {
 	__u32 msg_src_ip6[4];	/* Allows 1,2,4-byte read an 4-byte write.
 				 * Stored in network byte order.
 				 */
+	__bpf_md_ptr(struct bpf_sock *, sk);
 };
 
 /* User bpf_sock_ops struct to access socket values and specify request ops
@@ -3298,6 +3299,7 @@ struct bpf_sock_ops {
 	__u32 sk_txhash;
 	__u64 bytes_received;
 	__u64 bytes_acked;
+	__bpf_md_ptr(struct bpf_sock *, sk);
 };
 
 /* Definitions for bpf_sock_ops_cb_flags */
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog

[PATCH bpf-next 4/4] selftests/bpf: convert socket_cookie test to sk storage

[Stanislav Fomichev]

This lets us test that both BPF_PROG_TYPE_CGROUP_SOCK_ADDR and
BPF_PROG_TYPE_SOCK_OPS can access underlying bpf_sock.

Cc: Martin Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 .../selftests/bpf/progs/socket_cookie_prog.c  | 46 ++++++++++++-------
 .../selftests/bpf/test_socket_cookie.c        | 24 ++++------
 2 files changed, 38 insertions(+), 32 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
index 9ff8ac4b0bf6..0db15c3210ad 100644
--- a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
+++ b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
@@ -7,25 +7,35 @@
 #include "bpf_helpers.h"
 #include "bpf_endian.h"
 
+struct socket_cookie {
+	__u64 cookie_key;
+	__u32 cookie_value;
+};
+
 struct bpf_map_def SEC("maps") socket_cookies = {
-	.type = BPF_MAP_TYPE_HASH,
-	.key_size = sizeof(__u64),
-	.value_size = sizeof(__u32),
-	.max_entries = 1 << 8,
+	.type = BPF_MAP_TYPE_SK_STORAGE,
+	.key_size = sizeof(int),
+	.value_size = sizeof(struct socket_cookie),
+	.map_flags = BPF_F_NO_PREALLOC,
 };
 
+BPF_ANNOTATE_KV_PAIR(socket_cookies, int, struct socket_cookie);
+
 SEC("cgroup/connect6")
 int set_cookie(struct bpf_sock_addr *ctx)
 {
-	__u32 cookie_value = 0xFF;
-	__u64 cookie_key;
+	struct socket_cookie *p;
 
 	if (ctx->family != AF_INET6 || ctx->user_family != AF_INET6)
 		return 1;
 
-	cookie_key = bpf_get_socket_cookie(ctx);
-	if (bpf_map_update_elem(&socket_cookies, &cookie_key, &cookie_value, 0))
-		return 0;
+	p = bpf_sk_storage_get(&socket_cookies, ctx->sk, 0,
+			       BPF_SK_STORAGE_GET_F_CREATE);
+	if (!p)
+		return 1;
+
+	p->cookie_value = 0xFF;
+	p->cookie_key = bpf_get_socket_cookie(ctx);
 
 	return 1;
 }
@@ -33,9 +43,8 @@ int set_cookie(struct bpf_sock_addr *ctx)
 SEC("sockops")
 int update_cookie(struct bpf_sock_ops *ctx)
 {
-	__u32 new_cookie_value;
-	__u32 *cookie_value;
-	__u64 cookie_key;
+	struct bpf_sock *sk;
+	struct socket_cookie *p;
 
 	if (ctx->family != AF_INET6)
 		return 1;
@@ -43,14 +52,17 @@ int update_cookie(struct bpf_sock_ops *ctx)
 	if (ctx->op != BPF_SOCK_OPS_TCP_CONNECT_CB)
 		return 1;
 
-	cookie_key = bpf_get_socket_cookie(ctx);
+	if (!ctx->sk)
+		return 1;
+
+	p = bpf_sk_storage_get(&socket_cookies, ctx->sk, 0, 0);
+	if (!p)
+		return 1;
 
-	cookie_value = bpf_map_lookup_elem(&socket_cookies, &cookie_key);
-	if (!cookie_value)
+	if (p->cookie_key != bpf_get_socket_cookie(ctx))
 		return 1;
 
-	new_cookie_value = (ctx->local_port << 8) | *cookie_value;
-	bpf_map_update_elem(&socket_cookies, &cookie_key, &new_cookie_value, 0);
+	p->cookie_value = (ctx->local_port << 8) | p->cookie_value;
 
 	return 1;
 }
diff --git a/tools/testing/selftests/bpf/test_socket_cookie.c b/tools/testing/selftests/bpf/test_socket_cookie.c
index cac8ee57a013..15653b0e26eb 100644
--- a/tools/testing/selftests/bpf/test_socket_cookie.c
+++ b/tools/testing/selftests/bpf/test_socket_cookie.c
@@ -18,6 +18,11 @@
 #define CG_PATH			"/foo"
 #define SOCKET_COOKIE_PROG	"./socket_cookie_prog.o"
 
+struct socket_cookie {
+	__u64 cookie_key;
+	__u32 cookie_value;
+};
+
 static int start_server(void)
 {
 	struct sockaddr_in6 addr;
@@ -89,8 +94,7 @@ static int validate_map(struct bpf_map *map, int client_fd)
 	__u32 cookie_expected_value;
 	struct sockaddr_in6 addr;
 	socklen_t len = sizeof(addr);
-	__u32 cookie_value;
-	__u64 cookie_key;
+	struct socket_cookie val;
 	int err = 0;
 	int map_fd;
 
@@ -101,17 +105,7 @@ static int validate_map(struct bpf_map *map, int client_fd)
 
 	map_fd = bpf_map__fd(map);
 
-	err = bpf_map_get_next_key(map_fd, NULL, &cookie_key);
-	if (err) {
-		log_err("Can't get cookie key from map");
-		goto out;
-	}
-
-	err = bpf_map_lookup_elem(map_fd, &cookie_key, &cookie_value);
-	if (err) {
-		log_err("Can't get cookie value from map");
-		goto out;
-	}
+	err = bpf_map_lookup_elem(map_fd, &client_fd, &val);
 
 	err = getsockname(client_fd, (struct sockaddr *)&addr, &len);
 	if (err) {
@@ -120,8 +114,8 @@ static int validate_map(struct bpf_map *map, int client_fd)
 	}
 
 	cookie_expected_value = (ntohs(addr.sin6_port) << 8) | 0xFF;
-	if (cookie_value != cookie_expected_value) {
-		log_err("Unexpected value in map: %x != %x", cookie_value,
+	if (val.cookie_value != cookie_expected_value) {
+		log_err("Unexpected value in map: %x != %x", val.cookie_value,
 			cookie_expected_value);
 		goto err;
 	}
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog

Re: [PATCH bpf-next 1/4] bpf: export bpf_sock for BPF_PROG_TYPE_CGROUP_SOCK_ADDR prog type

[Daniel Borkmann]

On 06/12/2019 07:30 PM, Stanislav Fomichev wrote:
> And let it use bpf_sk_storage_{get,delete} helpers to access socket
> storage. Kernel context (struct bpf_sock_addr_kern) already has sk
> member, so I just expose it to the BPF hooks. Using PTR_TO_SOCKET
> instead of PTR_TO_SOCK_COMMON should be safe because the hook is
> called on bind/connect.
> 
> Cc: Martin Lau <kafai@fb.com>
> Signed-off-by: Stanislav Fomichev <sdf@google.com>

Looks good, applied, thanks!